Treating tar sands bitumen

ABSTRACT

(B) MAINTAINTAING THE SUPERFICIAL LINEAR VELOCITY OF THE DOOWNFLOWING LIQUID IN SEPARATION ZONE IN THE RANGE OF 0.006 TO 1.0 FOOT PER SECOND THE LOWER TEMPERATURE REQUIRING THE LOWER VELOCITY, (C) THE RANGE OF TEMPERATURE VERSOUS LIQUID VELOCITY BEING A SUBSTANTIALLY LINEAR RELATION OF TEMPERATURE VERSOUS A LOG-LOG SCALE OF DOWNFLOW LIQUID VELOCITY, (D) THE SPACE VELOCITY OF THE FEED THROUGH THE REACTION ZONE AND THE TEMPERATURE BEING SUCH THAT AT LAST 50 PERCENT OF THE FEED BOILING ABOVE 975*F. IS CONVERTED TO MATERIAL BOILING BELOW 975*F, (E) AND THEREBY AVOIDING COKING OF THE SEPARATOR.   1. IN A PROCESS FOR REFINING A TAR SAND DERIVED MATERIAL SELTED FROM THE GROUP CONSISTING OF NATURAL TAR AND BITUMEN, WHICH REFINING PROCESS INCLUDES THE STEPS OF PASSING THE FEED SUBSTANITALLY IN THE LIQUID PHASE THROUGH A REACTION ZONE IN THE PESENCE OF A HYDROGEN-CONTAINING GAS UNDER TEMPERATURE IN THE RANGE OF 700 TO 950*F. AND HYDROGEN PARTIAL PRESSURE IN THE RANGE OF 200 TO 1500 P.S.I. WHEREIN THE EFFLUENT IS REMOVED FROM THE REACTTION ZOZONE AND PASSED TO A SEPARATION ZONE AND WHEREIN THE EFFLUENT IS SEPARATED INTO AT LEAST A VAPOR FRACTION AND A LIQUID FRACTION, THE IMPROVEMENT WHICH COMPRISES: (A) MAINTAINING A TEMPERATURE IN THE SEPARATION ZONE IN THE RANGE OF 500*F. TO 800*F,

Oct. 15, 1974 Moeoeefv 564364709 apa/0 VZoc/W R. H. woLK EVAL TREATING 'un SANDS BITUMEN Filed Dec. 29. '1972 3,842,122 TREATING TAR SANDS BITUMEN Ronald H. Wolk, Trenton, and Michael C. Chervenak, Pennington, NJ., assignors to Hydrocarbon Research, Inc., New York, N.Y.

Filed Dec. 29, 1972, Ser. No. 319,315 Int. Cl. Cg 1/00, 9/16, 23/00 U.S. Cl. 208-48 Q 1 Claim ABSTRACT OF THE DISCLOSURE The recovery of valuable liquid hydrocarbons from tar sands bitumen by hydroconversion in an upflow reactor is improved when downstream equipment, including liquidgas separators, is operated under selected temperature and liquid velocity conditions to prevent coke formation and precipitation.

BACKGROUND OF THE INVENTION SUMMARY OF THE INVENTION We have now determined that there is a critical combination of the temperature of the liquid phase in the reactor eluent vapor-liquid separator and the downow liquid velocity in that separator that must be followed if coke formation in that separator is to be avoided. This correlation is based on a plot of the logarithm of the linear velocity against a linear temperature range which indicates that coke-free and coke-forming combination conditions exist. Some variation in the location of the line separating the coke-free and coke-forming zones will exist with bitumens of different characteristics as well as variations in the hydrogenation reactor conditions.

DESCRIPTION OF THE DRAWING FIG. 1 of the drawing is a schematic iigure of a preferred flow diagram for treating certain tar sands.

FIG. 2 is a graph of the coke-free versus coke-forming combination of conditions.

DESCRIPTION OF THE PREFERRED EMBODIMENT As more particularly shown in FIG. 1, a preheated natural tar bitumen feed including from 0.5 to 4 percent of silt, inorganic sand or the like, the particles of which are generally less than 325 mesh in size, is introduced through line 10 to a reactor 12 through line 14. A hydrogen rich gas (more than 60 percent hydrogen) is also introduced to the feed through line 14. This will include, as needed, a fresh make-up hydrogen in line and a recycle hydrogen in line 16.

Conveniently, all of the liquid with the ash and the gas are taken overhead in line 17 and passed to the separator 18. In this separator 18, which is at substantially reactor pressure, there will be a phase separation of gas and vapors which are removed overhead in line 20 and the liquid and ash which will be removed as bottoms through line 21. The liquid is then passed through pressure reducing valve 22 to low pressure separator 24.

'United States Patent O ice This separator chamber 24 is preferably operated at essentially atmospheric pressure to permit further removal of hydrogen and light hydrocarbons at 25, with the heavy oil containing the ash being removed at 26.

The vapors and gases that pass overhead at 20 from the high pressure separator 18 may be cooled at 28 and passed to separator 29, from which the gases such as hydrogen, methane, naphtha, etc. may be removed through overhead line 30. The hydrogen may be recovered by conventional processing and reintroduced in line 16.

The liquid fraction removed at 31 as bottoms from separator 29 is a gas oil boiling range material. This gas oil fraction may be injected into the liquid phase in separator 18 through line 31a to cause rapid cooling of the liquid phase. Alternately, it could be injected into line 17 through line 31b to quench the entire reactor eiiluent to the desired te-mperature. The amount of gas oil used is a function of the temperature at which it is injected and the desired temperature for the operation of the separator.

Under normal conditions, it is found that the hydrogen partial pressure in reactor 12 should be in the range of about 200 to 1500 p.s.i., hydrogen partial pressure. Temperatures will range from at least 700 F. but not to exceed about 950 F. Conversion of the 975 F. plus boiling range material to the material boiling below 975 F. will be in excess of 50%.

A total of eight experiments were run in which data on coke laydown in separators was obtained on three different bitumens. Three different bitumen feeds, designated 1, 2, and 3, were obtained from two different sources designated A and B. Coking in the separation zone was not encountered with feed 3B which contained 3.4 weight percent ash in Experiment I. Attempts to duplicate these experimental results in Experiment II were not successful with bitumen feed 1A which was obtained by a different extraction technique and contained 0.7 weight percent ash. The effect of the ash concentration on the coke laydown was evaluated in Experiment III. Feed 2A, containing 3.1 weight percent ash, was run and coke was obtained in the separation zone. This result indicated that the difference in the ash left in the bitumen after its extraction from the tar sand was not by itself suicient to prevent coke laydown. Experiment IV was then run with a hydrogen partial pressure in the reactor of 1200 p.s.i.g. instead of the 750 p.s.i.g. used for the first three experiments. A11 of these four experiments were at 68-73 percent conversion. The increase in pressure did not prevent coke laydown in the separation zone. Experiments V through VII were made at various separator temperature and liquid velocity combinations in an attempt to dene operable conditions. A plot of all the temperature and liquid velocity data, presented at FIG. 2, shows that there are two distinct zones defining conditions for coke laydown and coke-free operation for the separator. The data suggest that high ash feeds may be less likely to lay down coke than low ash feeds. However, in order to guarantee cokefree operation of the separator, it is necessary to stay above the minimum velocity and below the maximum temperature indicated by the lines in FIG. 2.

TABLE I Certain bitumens recovered from Athabasca tar sand have essentially the following characteristics:

TABLE IL EXAMPLES F RUNS Experiment I II IH IV V VI VII VIII Bitumen number and source-- 3B 1A 2A 1A 1A 1A 1A 1A Reactor temperature, Fm-- 84o 835 839 84o 805 805 805 805 Hydrogen partial pressure in reactor, p.s.i 750 750 760 1200 750 750 750 75o Conversion, volume percent (disappearance of 975 F., plus feed) 72 68 73 72 58 58 58 58 Separator temperature, F.. 700 675 800 800 550 650 700 800 Separation zone condition Clean Coked Ooked Coked Clean Coked Clean Clean Liquid phase velocity in separation zone, it./sec 0. 002 0. 002 0. 004 0. 004 0. 002 0. 001 0. 50 0. 80

The ordinate 40 is laid out on a log-log scale of super- (a) maintaining a temperature in the separation zone in ficial linear velocity of the downflowing liquid in separator the range of 500 F. to 800 F.; 18 and the abscissa 42 is laid out as a linear temperature (b) maintaining the superficial linear velocity of the Scale. The curves 44-46, which are relatively close dependdownflowing liquid in separation zone in the range ing on the bitumen, formed a demarkation line between of 0.006 to 1.0 foot per second the lower temperature the area A which proved to be representative of cokerequiring the lower velocity; free conditions, and area B, which generally showed 20 (c) the range of temperature versus liquid velocity objectionable coke formation. being a substantially linear relation of temperature It has been found essential to keep the eluent in the versus a log-log scale of downow liquid velocity; separator 18 down to a temperature between about 500 (d) the space velocity of the feed through the reaction and 800 F. and to maintain the downflow linear liquid zone and the temperature being such that at least 50 velocity between 0.006 and 1.0 foot per second. The lower percent of the feed boiling above 975 F. is c011- temperature corresponds to the lower velocity as shown verted to material boiling below 975 F.; 011 the CllfVeS in FIG- 2- A!! aPPfOXmae lilaf flnhf (e) and thereby avoiding coking of the separator. appears to exist between the lowest combination of conditions and the highest combination. References Cited While we have shown a preferred form of embodiment, UNITED STATES PATENTS we are aware that modications may be made thereto and 3 151 054 6 we, therefore desire a broad interpretation of the inven- 3 2 9/19 4 Laylg 208 11 tion within the scope and spirit of the disclosure herein 2 4959 12/1965 Schhngef et al' 208-107 3,544,447 12/1970 Van Driesen 208-48 and the claim appended theremafter.

We claim: 3,553,105 1/1971 Layng et al 208-213 1. In a process for refining a tar sand derived material gacgrletsenl --ZgS-E selected from the ou consistin of natural tar and g l e a gf P g 3,725,247 4/1973 Johnson et al. 208-111 bitumen, which refining process includes the steps 0f passing the feed substantially in the liquid phase through a reaction zone in the presence of a hydrogen-containing gas under temperature in the range of 7 00 to 950 F. and hydrogen partial pressure in the range of 200 to 1500 p.s.i. wherein the efuent is removed from the reaction zone and passed to a separation zone and wherein the eluent is separated into at least a vapor fraction and a liquid fraction, the improvement which comprises:

DELBERT E. GANTZ, Primary Examiner G. E. SCHMITKONS, Assistant Examiner U.S. C1. X.R. 

1. IN A PROCESS FOR REFINING A TAR SAND DERIVED MATERIAL SELTED FROM THE GROUP CONSISTING OF NATURAL TAR AND BITUMEN, WHICH REFINING PROCESS INCLUDES THE STEPS OF PASSING THE FEED SUBSTANITALLY IN THE LIQUID PHASE THROUGH A REACTION ZONE IN THE PESENCE OF A HYDROGEN-CONTAINING GAS UNDER TEMPERATURE IN THE RANGE OF 700 TO 950*F. AND HYDROGEN PARTIAL PRESSURE IN THE RANGE OF 200 TO 1500 P.S.I. WHEREIN THE EFFLUENT IS REMOVED FROM THE REACTTION ZOZONE AND PASSED TO A SEPARATION ZONE AND WHEREIN THE EFFLUENT IS SEPARATED INTO AT LEAST A VAPOR FRACTION AND A LIQUID FRACTION, THE IMPROVEMENT WHICH COMPRISES: (A) MAINTAINING A TEMPERATURE IN THE SEPARATION ZONE IN THE RANGE OF 500*F. TO 800*F, 